Mewtwo is an unlockable character and can be unlocked by playing a combined minimum 20 hours of single player and multiplayer matches or playing at least 700 Melee matches. Its main stage is Pokémon Stadium.

Mewtwo has an unusual combination of attributes. Unlike other characters, its throws are exceedingly powerful, capable of KO'ing at similar percentages as smash attacks. It also boasts several fast attacks that can be linked together for simple and effective combos, and possesses an exceptional recovery. However, it is rather light, moves and falls slowly, and is a large target, making it easy to combo back. It also has difficulties KO'ing opponents - while its throws are strong, it needs to get grabs first, and its other KO moves are either slow or have short range.

Trophy information

Classic Mode

A genetically created Pokémon, Mewtwo is the result of many long years of research by a solitary scientist. Although Mewtwo was cloned from the genes of the legendary Pokémon Mew, its size and character are far different than its ancestor. Its battle abilities have been radically heightened, making it ruthless.

Adventure Mode

As Mewtwo relies mostly on its powerful brain, there are times when it scarcely uses its arms and legs. Since Mewtwo spends much of its time floating, it flies far when struck. Shadow Ball traces a jagged path once released; the longer Mewtwo holds it, the more powerful it becomes. Mewtwo uses Confusion to spin its foes around.

All-Star Mode

Mewtwo is definitely not a speedy character, but its ESP-powered grab and throw moves are comparatively strong. Teleport has a short range, but doesn't leave it open to attack. It's best used as an escape move during disturbances. Mewtwo can daze a foe if it makes eye contact and uses Disable; the move is useless unless Mewtwo is facing its enemy.

Although Mewtwo is not a playable character, there are several empty files for unused playable characters, one of which is named "mewtwo".

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A Genetic Pokémon. This legendary Pokémon was based on a recombination of Mew's DNA, created by a scientist after years of research. However, Mewtwo greatly differs from Mew in both size and personality and it is said to have the most twisted and savage heart among all Pokémon. Mewtwo has incredibly high combat abilities and uses Psychic-type attacks.

Mewtwo returned as a downloadable bonus character. It was confirmed to be a playable character during the Super Smash Bros. for Wii U: 50-Fact Extravaganza on October 23, 2014. It was free for players who have bought both the 3DS and Wii U versions and have registered both to Club Nintendo by March 31, 2015, and those who received the code could redeem and download Mewtwo as early as April 14, 2015. However, Mewtwo is also purchasable for a small fee if one did not buy both games or did not register both to Club Nintendo. It became available to the public for purchase on April 28, 2015.

Mewtwo is now voiced by Keiji Fujiwara, replacing Masachika Ichimura's work from Super Smash Bros. Melee. As in Melee, Mewtwo has fully voiced victory quotes in Japanese (which are re-recorded versions of its Melee quotes), which are removed for international versions. It continues to be based on the original series' Mewtwo from the anime, marking the character's first appearance in any new media since Melee itself as well as Mewtwo Returns. Its attributes were tweaked from its Melee appearance, decreasing its weight but also improving its mobility and its special moves, making it a much more useful but more difficult character overall (especially with a multitude of buffs in the later patches of the game).

Mewtwo also appears in both versions as a normal trophy. Both versions of Mega Mewtwo appear as a single trophy in the Wii U version, with Mewtwo appearing as Mega Mewtwo Y (with a silhouette of its regular form) for its Final Smash trophy.

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Mewtwo (fighter)

NA:Mewtwo puts its psychic powers to great use in this game. Not only does it have floaty jumps, but its telekinesis gives its attacks extra reach and its throws added power. However, its light body makes it easy to launch, so if you're willing to take the risk of getting in close, it might just be worth it!

PAL:Mewtwo puts its psychic powers to great use in this game. Not only can it float in midair, but its telekinesis gives its attacks extra reach and its throws added power. However, its light body makes it easy to launch, so if you're willing to take the risk of getting in close, it might just be worth it!

Mewtwo (Alt.)

NA:Mewtwo's Confusion side special not only repels projectiles—it also reflects the damage back on your opponent. Its down special, Disable, stuns an enemy for longer the higher its damage is. Disable only works on foes that are facing Mewtwo.

PAL:Mewtwo's Confusion Side Special not only lets you repel projectiles, it also reflects the damage back on your opponent. Its Down Special, Disable, stuns an enemy for longer the higher its damage is. As it works by having Mewtwo glare at its foe, this only works if they make eye contact.

Psystrike

Mewtwo's Final Smash starts as Mewtwo Mega Evolves into Mega Mewtwo Y. It then fires a huge psychic projectile that penetrates enemies and obstacles. This projectile doesn't do any damage, but it freezes every foe it hits in place. They can even be frozen midjump! Afterward, every foe hit with this projectile will take a powerful psychic hit to the head.

Mewtwo (non-fighter)

Created from modified Mew DNA, Mewtwo was designed to be the ultimate Pokémon. It didn't take on any of Mew's kinder traits and only uses its intelligence to destroy its enemies. Or...so it seems. Perhaps it just feels frightened or even tormented, and that's why it lashes out. Whatever the reason, Mewtwo is not to be messed with.

Mega Mewtwo X & Y

NA:It's almost no surprise that a Pokémon as powerful as Mewtwo wouldn't be limited to a single Mega Evolution. Mega Mewtwo X has strong arms and legs, while Mega Mewtwo Y has a whiplike, slender head. The differences aren't just physical - X brings improved fighting power, while Y can unleash even more psychic power.

PAL:Mega Mewtwo comes in two forms rather than just one. Mega Mewtwo X has visibly strengthened limbs, which greatly boost its physical abilities in battle. Mega Mewtwo Y, on the other hand, has a whip-like tendril extending from the back of its head, which augments its psychic powers.

Classic Mode

Mewtwo's Classic Mode route is called Psychic Control. In it, after Mewtwo completes a round, one of its opponents joins it as an ally in the next fight in an alternate costume. This ally is often one, or represents one, that has been brainwashed in their series, and is likely a reference to Mewtwo Strikes Back, where Mewtwo controls a Nurse Joy to act as a proxy.

World of Light

In the opening cutscene of World of Light, Mewtwo tried to reflect the beam of light with Confusion, alongside Zelda, who used Nayru's Love, but the light pierced through their special attacks and obliterated them regardless.

Mewtwo's fighter icon isn't found until the player reaches the World of Dark, in the Mysterious Dimension subarea. It appears after the player completes the fight with Whispy Woods's spirit.

While most characters have a unique Palutena's Guidance conversation starring the Kid Icarus characters, Mewtwo and other DLC characters share a generic conversation where the Kid Icarus characters note their lack of information on the fighter.